This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A354421 #10 Jun 08 2022 10:14:47
%S A354421 1,0,-2,-6,-12,-10,60,406,672,-18666,-400740,-6617842,-108686952,
%T A354421 -1883464466,-34930602252,-693981413610,-14732243810016,
%U A354421 -333084114060442,-7994768036250132,-203102355108133154,-5445884954606704920,-153726156157794541986
%N A354421 Expansion of e.g.f. (2 - exp(x))^x.
%F A354421 a(0) = 1; a(n) = -Sum_{k=1..n} A052862(k) * binomial(n-1,k-1) * a(n-k).
%F A354421 a(n) ~ -n! / (Gamma(1 - log(2)) * 2^(-log(2)) * n^(log(2) + 1) * log(2)^(n - log(2) - 1)). - _Vaclav Kotesovec_, Jun 08 2022
%o A354421 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace((2-exp(x))^x))
%o A354421 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=-sum(j=1, i, j*sum(k=1, j-1, (k-1)!*stirling(j-1, k, 2))*binomial(i-1, j-1)*v[i-j+1])); v;
%Y A354421 Cf. A052862, A354239, A354413.
%K A354421 sign
%O A354421 0,3
%A A354421 _Seiichi Manyama_, May 26 2022